Machines such as, for example, excavators, loaders, dozers, and other types of heavy machinery typically have a large number of hydraulically controlled implements (such as, for example, a bucket, grapple, or hammer) selectably attachable to the machine. The hydraulic systems controlling the tools typically include multiple hydraulic actuators (e.g., piston-cylinder arrangements and/or hydraulic motors) that work in conjunction with a linkage system to affect movement and operation of the tool. Movement of the hydraulic actuators is controlled by various operator input devices, such as one or more control levers, foot pedals, switches, or joysticks.
In addition to selectably attaching tools, a linkage system may also be replaced. The types of tools and linkage system attachable to the machine, as well as the couplers that attach the tools to the machine, often have different shapes, sizes, weights and/or other properties. As such, different combinations of tools and linkage systems (i.e., different implement configurations) may affect the motion control of the machine and react to operator inputs differently. For example, a relatively heavier tool and/or a relatively longer linkage system may establish a relatively greater force moment, caused by the implement configuration, about the machine with respect to a relatively lighter tool and/or shorter linkage system.
One method of improving the motion control of tools is described in U.S. Pat. No. 5,784,945 (the '945 patent) issued to Krone et al. The '945 patent describes an apparatus for determining a valve transform curve in a fluid system. The fluid system includes a fluid actuator with a valve arranged to initiate movement of a load. The system of the '945 patent determines a desired velocity of the fluid actuator based on a sensed load or position of the fluid actuator and generates a valve transform curve to achieve the desired velocity.
Although the system of the '945 patent may improve motion control of the fluid actuator for different loads associated with the actuator, the system of the '945 patent may not provide flexibility when controlling different implement configurations via the same machine. For example, one implement configuration may function undesirably under a given input device position/load/command velocity relationship as compared to another implement configuration attachable to the same machine. Additionally, the system of the '945 patent may not allow the velocity relationship of the fluid actuator to be modified or selected based on different tool and linkage configurations.
The disclosed method and apparatus are directed to overcoming one or more of the shortcomings set forth above or other shortcomings in the art.